This invention relates to a convenient process for producing amine derivatives having the action of inhibiting the secretion and accumulation of amyloid xcex2 protein and useful as a pharmaceutical preparation, as well as useful synthetic intermediates thereof.
As amine derivatives having the action of inhibiting the secretion and accumulation of amyloid xcex2 protein and a process for producing the amine derivatives, the following process is described in JP-A 11-80098.
[formula]
wherein W represents a hydrogen atom or a protective group, Xa represents an oxygen atom etc., Y represents an optionally substituted divalent C1-6 aliphatic hydrocarbon group (excluding methylene) which may be bound via an oxygen atom or a sulfur atom, R1 and R2 each represent a S hydrogen atom or an optionally substituted lower alkyl, or may, together with their adjacent nitrogen atom, form an optionally substituted nitrogen-containing heterocyclic ring, ring A represents a benzene ring which may further have a substituent group, ring B represents a 4- to 8-membered ring which may further have a substituent group, Ar represents an optionally substituted ring-assembled aromatic group or an optionally substituted condensed aromatic group, Xb represents a bond etc., and L represents an leaving group or hydroxy.
In the process described above, the amide moiety of Compound (IVa) is reduced to give Compound (Va), and then the ether linkage is cleaved to give Compound (IIa). This is because, when an amide linkage and an ether linkage are present in the same molecule, selective cleavage of the ether linkage is generally difficult and thus the amide linkage is also simultaneously cleaved.
In the above process, it was revealed that in the step of subjecting Compound (IIa) to alkylation reaction to form Compound (Ia), the tertiary amine is also alkylated to form a quaternary amine salt, thus causing a reduction in the yield of the desired amine derivative.
There is demand for development of a convenient and industrially advantageous process for producing an amine derivative having the action of inhibiting the secretion and accumulation of amyloid xcex2 protein.